IR proximity sensor

Thread Starter

Metoo25

Joined Sep 7, 2020
13
Hello. I am currently working on a project, where I have to build a people counter using IR.
I need a transmitter and a receiver that would work well together. It has to work on a range from the sensor and up till 80cm. I am not looking to measure the distance, just want to know whenever someone/something is there or not.

My question is. Does anyone know any transmitter and a receiver that work well together and work up to 80 cm?

Please let me know if you have any questions.

Best regards
metoo25
 

Sensacell

Joined Jun 19, 2012
2,758
Use an el-cheapo red laser and a phototransistor. So easy.

IR is going to be more difficult (as you cannot see the light) and you will probably need to resort to modulating the light source and demodulating it to get a reliable 80 cm range.
 

jpanhalt

Joined Jan 18, 2008
11,088
This is one of hundreds of examples of IR receivers: http://www.farnell.com/datasheets/2049301.pdf
Transmitter is simply a diode or laser of the appropriate wavelength and pulsed by an MCU or any appropriate oscillator (e.g., a pair of 555's) .
Directionality can be improved by using light tubes, e.g., put the detector at the end of a 6 mm diameter tube. Paint inside of tube black to reduce reflections.
 

Thread Starter

Metoo25

Joined Sep 7, 2020
13
This is one of hundreds of examples of IR receivers: http://www.farnell.com/datasheets/2049301.pdf
Transmitter is simply a diode or laser of the appropriate wavelength and pulsed by an MCU or any appropriate oscillator (e.g., a pair of 555's) .
Directionality can be improved by using light tubes, e.g., put the detector at the end of a 6 mm diameter tube. Paint inside of tube black to reduce reflections.
I will look at this. Thank you
 

KeithWalker

Joined Jul 10, 2017
1,599
Are you trying to detect people by breaking a beam or by reflection?
If you are breaking a beam, a laser pointer and photoresistor (LDR) is definitely the simplest and most reliable solution.
If you are trying to detect a reflected beam, you will need a much more sophisticated system. To get anything close to the sensitivity you specified, you will need a modulated source, with a detector tuned to the frequency of modulation. You will also need to have some basic focusing on the transmitter source and the receiver. Cloth does not reflect IR very well, especially in darker colours.
If you are limited to using a reflective method, I would suggest using ultrasonics instead. The HC-SR04 ultrasonic transmitter/receiver would be a good choice. It is inexpensive and easy to use.
Regards,
Keith
 
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